WO1996025539A1

WO1996025539A1 - Process for the melt spinning of polyurethane and/or polyurethane urea

Info

Publication number: WO1996025539A1
Application number: PCT/DE1996/000235
Authority: WO
Inventors: Gottfried Schauer; Matthias BRÄUER; Cornelia Bellmann; Dieter Lehmann; Bernhard TÄNDLER; Rainer Hagen; Friedrich Weger
Original assignee: Karl Fischer Industrieanlagen Gmbh
Priority date: 1995-02-13
Filing date: 1996-02-13
Publication date: 1996-08-22
Also published as: KR100235215B1; EP0809723B1; CN1071383C; CN1180386A; KR19980702182A; DE59609591D1; DE19504671C1; EP0809723A1

Abstract

The invention concerns a process for the melt spinning of polyurethane and/or polyurethane urea, in which: a) a prepolymer is produced which contains the product of reaction of an organic diisocyanate and a polymer diol by mixing at between 50 and 150 °C; b) the temperature level is reduced by approximately 5 to 50 K and a gel and/or melt additive is added in the fluid state; c) the prepolymer is mixed with a chain extender and reaches its molten state by stirring; d) the prepolymer is fed in the molten state to an extruder in which polymerization occurs at a higher temperature; and e) the polymer melt is spun by spinning nozzles to form polyurethane and/or polyurethane urea threads.

Description

Process for melt spinning polyurethane and / or polyurethane urea

The invention relates to a process for melt spinning polyurethane and / or polyurethane urea, in which a prepolymer is produced which contains a melting aid, a device for carrying out the process and the threads produced by this process.

A thermally stable melt of polyurethane and / or polyurethane urea elastomers is known from EP 0 553 944. This melt is produced by a polyaddition or build-up reaction of longer-chain diols with diisocyanate, chain extender and a polar gel and / or melting aid. Carboxylic acid amide is proposed as a gel and / or melting aid. This application further describes that this Melt can be processed into shaped articles. Melt spinning is mentioned as a method here. However, no further details are disclosed of how this melt spinning of this melt is to be carried out.

It has been shown that it is only possible to a very limited extent to use the melt which can be produced according to EP 0 553 944 for melt spinning. Either spinning was not possible or only threads with insufficient physical properties were obtained.

Proceeding from this, it is therefore the object of the present invention to provide a process for melt spinning polyurethane and / or polyurethane urea elastomers, with which threads are obtained which have comparable physical properties to those which have previously been achieved by solvent spinning.

According to the method, the invention is solved by the characterizing features of claim 1 with respect to the device by the features of claim 34 and in view of the threads produced by this method by the characterizing features of claim 46. The subclaims advantageously show continuing education.

According to the invention, it is therefore proposed to first produce a prepolymer in a first process step (process step a), which contains a reaction product of an organic diisocyanate and a polymeric diol and then only in a second subsequent process step (process step b) Cool this prepolymer to add 10 to 50 K of the gel and / or melting aid. This prepolymer thus produced is then mixed with a chain extender while maintaining its molten state (process step c) with stirring. It is essential that this prepolymer, as described above, is fed to an extruder in the molten state and then the polymer melt obtained is then spun through spinnerets to form polyurethane and / or polyurethane urea threads. The exact sequence of method steps a to e is essential to the invention. It has been shown that polyurethane and / or polyurethane urea filaments with useful physical properties can only be obtained if the process sequence described above is observed.

In the preparation of the prepolymer (in process step a) the procedure is such that preferably the

Starting components, ie the diol and the organic diisocyanate, are introduced separately in the liquid state and then reacted in a suitable reaction vessel, for example a stirred reactor. The reaction temperature depends on the selected starting components, but is preferably in the range from 50 to 150 ° C. The reaction is carried out until a complete or almost complete reaction of the diol with the diisocyanate is achieved. It is preferred if a ratio of diol to diisocyanate (in moles to moles) of 1: 1.1 to 1: 10.0 is maintained. The molar ratio of 1: 1.4 to 1: 4 is particularly preferred. The starting compounds can be used in pure form or as a mixture. From a material point of view, the Invention includes all of the diisocyanates or polymeric diols known to date for the production of polyurethane and / or polyurethane urea. The invention includes in particular the compounds mentioned in EP 0 553 944. It is preferred if uncapped and / or capped diisocyanate is used as the organic diisocyanate. The use of hexamethylene diisocyanate is particularly preferred. In the case of the diols, the hydroxypolyethers and / or the hydroxypolyesters are preferred. The use of polytetrahydrofuran is very particularly suitable for the process according to the invention. The polymeric diols preferably have a molar mass of 1000 to 3000 g / mol and a molar mass ratio of M _w / M _n ^< 2.degree. _' Compliance with these conditions has proven to be particularly favorable for the properties of the threads. An influencing of the product properties is possible through the different installation of the hard segments in statistical or non-statistical distribution.

It is crucial in the process according to the invention that the prepolymer prepared as described above is kept in the molten state and then the temperature level of this molten phase is lowered by 5 to 50 K, preferably by 10 to 30 K. Only then is a gel and / or melting aid in the liquid state added. In this process step it should be noted that the liquid gel and / or

Melting aid must be evenly distributed in the prepolymer, which can best be accomplished by intensive stirring in the stirred reactor. 1 to 25% by mass, based on the prepolymer, of the gel and / or melting aid is preferably added. 2 to 10% by mass are particularly preferred. From a material point of view, the procedure is particularly preferably such that a carboxamide and in particular e-caprolactam are used as the gel and / or melting aid.

After the gel and / or melting aid has been added, a chain extender is added, likewise with vigorous stirring. The intensive stirring at this stage of the process also has the task of achieving an almost complete and homogeneous distribution of the chain extender in the prepolymer prepared as described above. Alternatively, however, it is also possible that the chain extender is not used after the addition of the gel and / or melting aid, but at the same time as the gel and / or melting aid. The chain extender can alternatively be fed into the extruder. Suitable chain extenders here are all chain extenders known to date from the prior art for the production of polyurethane and / or polyurethane urea melts. Examples include aliphatic dihydroxy compounds, aliphatic and / or arylaliphatic hydroxyamine compounds, aliphatic and / or aromatic diamine compounds or mixtures thereof. In the method according to the invention, it is also possible for trifunctional chain extenders to be used for the modification. This serves e.g. to improve the dyeability.

The amount of chain extender is determined by the specified molar ratio of diol to diisocyanate (1: 1.1 to 1:10). The method described above and the subsequent production of the fibers achieve hard segment fractions of 10 to 30, preferably 15 to 25% by mass.

In order to achieve specific properties in a targeted manner, it is also possible to add additives to the prepolymer in process steps a, b and / or c. The additive, like the chain extender, can also be fed directly to the extruder. Examples of such

Additives are stabilizers (e.g. heat stabilizers) plasticizers, lubricants, spinning aids, flame retardants, pigments, dyes, color aids or emulsifiers. Sterically hindered phenol and phosphorus compounds are suitable as stabilizers against thermal degradation and oxidative degradation, e.g. Esters of phosphoric acid (e.g. triphenylphosphate), phosphorous acid (e.g. triphenylphosphite), phosphonic acid (e.g. diethylethoxycarbonylmethylphosphonate), phosphonous acid (e.g. benzenephosphonous sodium salt) and salts of phosphoric acid (e.g. sodium polyphosphate). Examples of a sterically hindered phenol are the phenol with the CAS number 6683, examples of UV and light stabilizers are compounds of the benzotriazoles.

In this preparation of the prepolymer according to process steps a to c, as described above, it is important that work is carried out with pure starting products, ie with pure diisocyanate, polymeric diol, gel and / or melting aids, chain extenders and optionally additives. The transport, storage and processing are therefore preferably carried out under inert gas and in the absence of oxygen, acid gases and moisture. This can be done, for example, by flushing the reaction vessel with inert gas until it is free of oxygen and water. For dewatering the diol component, it is preferred that this is carried out under vacuum (several hours under vacuum with 1 to 60 mbar and elevated temperature), possibly with the use of drying agents. A thin-film apparatus can also be used for larger throughputs and for the simultaneous removal of gas inclusions. The maximum permitted moisture content should not exceed 30 ppm.

The viscosity of the prepolymer as described above is in the range from 1 to 200 Pa s at 80 ° C., and the molecular weight of the prepolymer increases

Values from 1,000 to 5,000 g / mol. In the process according to the invention, it is particularly advantageous that the polyurethane and / or polyurethane urea threads are produced using such a prepolymer, because this prepolymer is already homogeneous

Reaction system represents, so that a polymerization can now only be targeted by increasing the temperature.

According to the invention, the polyaddition reaction is continued in an extruder. As a result, there is the possibility that the polyaddition conditions can be specifically set and thus also influenced by the dimensioning and the operation of the extruder. A twin-screw extruder is preferably used, in which the screws are closely intermeshing and have a high self-cleaning effect and at the same time are good mixing and shearing. The screws are preferably configured so that the residence time is as narrow as possible. is achieved to achieve a uniform product quality. The screws have a high L / D ratio (20 to 60, preferably 25 to 60). The extruder is operated with a temperature profile with high temperature constancy over time.

The polymer melt obtained after process step d is spun through spinnerets to form polyurethane and / or polyurethane urea filaments. As an alternative to the process sequence described above, however, it is also possible to cool and store either the prepolymer produced by process step c or the polymer melt obtained after process step d and only melt it again when necessary and the corresponding further Ver ¬ to carry out driving steps. With the prepolymer after process step c, it is also possible to store it in the liquid state. It has been shown that in particular the prepolymer melt, which was obtained after process step c, can be stored for at least one week even without stabilizers which increase storage stability, with the exclusion of air. The same applies to the cooled polymer melt which was obtained after process step d. This can also be kept for at least one week in the absence of air.

As already described above, the melt is spun into the corresponding threads via spinnerets. Depending on the reaction-typical and temporal

In the course of the polyaddition of the chemical system used, a polymer melt, which is characterized by a specific melt viscosity value, reaches the spinning head. This viscosity value can be between 150 and 10,000 Pa s, measured at the temperature of the melt line.

The melt viscosity in certain areas can be influenced with the spinning head temperature by higher temperatures lowering the viscosity. It is important that the viscosity immediately before the spinneret does not exceed 3,000 Pas. The temperatures of the spinning head are preferably kept in a range from 210 to 240 ° C. Too high

Temperatures harbor the risk of polymer degradation beginning.

The design of the spin pack should be mentioned as a further measure to improve the spinning conditions. The spin pack preferably consists of one or more filter elements, which can consist of filter cloth, metal fiber fleece inlays, sintered metal plates or sand fillings, sealing elements and support elements, and the spinneret plate.

Particularly in the case of the higher-viscosity melts with a high storage modulus, as is usually the case with polyurethane and / or polyurethane urea melts, it is important to avoid turbulence in the bore channels of the spinneret plate. Continuously tapering inlet channels beginning at the top of the spinneret plate are favorable, which lead to spinning bores of preferably 0.3 to 0.9 mm in diameter and 0.5 to 3 times this value as length. The number of bores per spinneret plate, the emerging filaments of which form the thread to be wound up, can vary between one and a plurality. After the melt jets have emerged from the spinning nozzle into the free space, they have to cool in order to solidify. The cooling is preferably carried out here in a cooling shaft, which can be ventilated transversely or parallel to the direction of rotation. The resulting exhaust air is sucked off and carried away.

A further preferred embodiment proposes that the filaments are passed through a post-heating zone after leaving the spinnerets, but before the cooling shaft. Instead, a zone can also be used in which warm air is coated, e.g. with air or inert gas. Depending on the polymer composition and process control, lengths of 100 to 300 mm and heating temperatures of 50 to 200 ° C have to be taken into account for the post-heating section. This measure has proven itself due to the better structure of the filaments. However, it is also possible to find good spinning and thread properties with no need for post-heating.

The further cooling conditions of the filaments realized in the cooling shaft are determined by the speed of the air moving in cross-flow to the longitudinal axis of the cooling shaft and its temperature. Limit values can be 0.2 to 1.0 m / s and 10 to 80 ° C. For parallel flow, values from 0.3 to 3 m / s are suitable, at temperatures between 10 and 80 ° C.

Before the filaments are finally solidified and given a preparation coating, they should touch and glue to one another to form a closed dressing from which none individual filaments emerge that could interfere with the further processing of the thread. The bundling of the filaments at one point of the preparation device can give rise to the stirring. However, additional aids such as false twist devices can also be switched into the path of the filaments.

Special oily preparations are used for the preparation, which, pumped and precisely metered, are transferred to the thread by means of fork-shaped guide elements. Also known are circumferential disks immersed in the preparation liquid, from which the filaments or the thread strips and accepts part of the liquid film. In addition to the specific properties of a preparation, the amount remaining on the thread determines the processability of the thread. This amount is determined using known extraction methods. The percentage based on the thread should be higher than 3%. The threads are then drawn off from the spinning zone, preferably with godets. The take-off speed with which this can be carried out varies within wide limits and is dependent on the polymer and the desired thread properties, in particular the fineness of the thread. The speed can range from 50 to 1,000 m / min. Depending on the desired property profile, the thread in this time phase of its formation can also be caused by the effect of heat from the heated godets or by heating of the threads achieved by other means (heating rails, heating nozzles) in conjunction with unheated godets partially stretched plastically. The level of stretching determines the fineness of the thread and has an influence on its strength, stretching and the elastic stretch component.

Depending on the selected polymer compositions and process engineering conditions, the threads according to the invention are of a certain fineness, strength, elongation and elasticity. With a subsequent heat treatment of the thread, for example on the bobbin, with a temperature of 60 to 130 ° C and a heat treatment time of 1 to 48 hours, the property values for strength, elongation and elastic percentage of stretch can be increased again. The heat treatment is preferably carried out with exclusion of air and moisture.

Instead of bundling the individual filaments into a thread and winding it onto a spool, the filaments can also be deposited in the form of a spunbonded web using known means.

In addition to thread production, the present method can also be used for the production of wires and profiles and other plastic semi-finished products based on polyurethane or polyurethane urea. For this purpose, an extrusion tool with known draw-off and winding-up or cut-to-length devices is subsequently arranged on the extruder.

Further features, details and advantages of the invention emerge from the following description of two preferred embodiments for the production of the threads and with the aid of examples. It shows: 1 shows the schematic structure of the device part for producing the polymer melt,

2 shows the schematic structure of the spinning device with a cooling shaft which is ventilated transversely to the direction of the thread,

3 shows the schematic structure of the spinning device, a cooling shaft with ventilation parallel to the direction of rotation being provided.

Figure 1 shows an exemplary embodiment for the preparation of the prepolymer, i.e. the device, which includes the process steps a to d.

The temperature of the liquid or molten starting components (diol, diisocyanate, melting aid and chain extender) is carried out according to the exemplary embodiment according to FIG. not shown). The temperature can also be controlled using external heat exchangers. The transport, storage and processing of the reactants is preferably carried out under inert gas and with the exclusion of oxygen and acid gases, such as carbon dioxide and moisture. With the aid of the metering units 5 to 8, the starting components are metered in batches via temperature-controllable pipes 11 into a stirred reactor 16. A feed 10 is additionally provided for metering additives and can be controlled by means of the metering pump 9. The determination of the necessary quantities can, for example both volumetric and gravimetric. The stirred reactor 16 is equipped with a temperature control system. The temperature is preferably controlled by vaporous or liquid heat transfer media. The heating or cooling output is regulated according to the temperature measured in the product room with a sensor 15 and is kept at the desired temperature. The prepolymer is produced in the stirred reactor 16, preferably under ambient pressure. Depending on the vapor pressure of the starting components used, operation under elevated pressure may also be necessary. The stirring reactor 16 is equipped with an agitator drive 14 which is variable in speed. The products discharged with the inert gas flushing can be condensed out and returned in a condenser 13 charged with cooling medium. If necessary, the stirring reactor is evacuated via the pipeline 12 for drying purposes or degassing can be carried out. The polyaddition reaction is continued in a twin-screw extruder 49. In the embodiment according to FIG. 1, a twin screw extruder running in the same direction is provided. The screws 19 are tightly intermeshing with a high self-cleaning effect, good mixing and shearing. The screws 19 are configured so that the narrowest possible residence time range is achieved in order to achieve a uniform product quality. The screws 19 have a high L / D ratio (20 to 60, preferably 25 to 60). The extruder 49 is operated with a temperature profile with high constancy over time. The extruder 49 is heated here by means of individual electrical heating jackets 21. In addition to the housing temperatures, which are regulated by the heating jackets 21, the product temperatures, the temperature in the draft shaft 20, the measurement of the torques and the pressure in the extruder and at the outlet from the extruder 22 are necessary for control and regulation processes. It has been shown in tests that in the embodiment according to FIG. 1 temperatures of 250 ° C. should not be exceeded.

The prepolymer from the stirred reactor 16 is metered into the extruder feed shaft 20 via a heated line 17 and the conveying device 18, preferably a gear pump, in such a way that complete filling of all screw flights is ensured while the machine is running. It is also possible to work with several extruders 49. In this case, the heated line 17 can then be divided according to the number of extruders 49, or separate lines can be used. The temperature in the feed shaft 20 is below the reaction temperature of the chain assembly reaction. The polymerization rate of the polymer build-up reaction to the melt which can be processed in a thermoplastic process is controlled via the temperature regime of the extruder 49. The pressure difference (inlet / outlet) building up in extruder 49 should assume values <100 bar, since backflow effects and excessive shear, which can reduce the product quality, are to be avoided. A minimum pressure must be present on the suction flange 22 of the heated pressure pump 23 for stable delivery. The extruder 49 is preferably operated in the feed shaft 20 without pressure. Alternatively, the prepolymer or individual components can also be fed in under pressure. For example, the chain extender and additives can also be fed into corresponding mixing zones only in the extruder 49. The melt line 24 is to be tempered exactly. The printing Falling in the melt line provides statements for the control of the polymer build-up reaction during operation under otherwise constant conditions of temperature and throughput.

Figure 2 now shows a schematic structure of the spinning part of the device. The polymer melt reaches the spinning head 25 via the heatable melt line 24. The spinning head 25 has the task of converting the polymer melt into individual melt jets which solidify in the downstream cooling shaft 57 to form filaments 27. The cooling shaft 57 in the embodiment according to FIG. 2 essentially consists of a cylindrical device 26. For transporting the melt in the melt line 24, there is a motor-driven gear pump 28, known as a spinning pump, which pumps the melt with a high level of accuracy and consistency over time into the spinning head 25 integrated interchangeable spin pack 29 presses. The spin pack 29 consists of filter elements for cleaning the conveyed melt, sealing and support elements and the spinneret plate 30.

Metal wire and metal fiber fleece filter sieve inserts are generally suitable for cleaning the melt, but also fine sand packs or sintered metal plates, for example. The latter have a double function. In addition to the filter effect, the high energy input required for the viscous medium to flow through these plates

Melt is necessary, a heating of the melt, immediately before it enters the nozzle bore. The temperature increase in the melt arises from dissipation (friction when flowing through the sintered metal plate). With the warming of the Melt is usually accompanied by a lowering of the viscosity thereof, which can favor the subsequent spinning of the thread.

The spinning head 25 as a whole is surrounded by a double jacket which can be heated by liquid or steam or by an electric heating jacket 31 and is thermally insulated 32. A sensor 33 inside detects the current temperature and initiates its regulation according to the setpoint. Furthermore, there is a pressure sensor 34 in the melt stream downstream of the spinning pump 28, which monitors the so-called spinning pressure and reveals process irregularities and the filter occupancy rate.

After the melt jets have emerged from the spinning nozzle 30 into the free space, they have to cool in order to solidify. For the structure formation beginning in the individual filaments, it may be desirable or necessary to slow down the cooling in the first section following the spinneret 30. The heated tube 35, which can be varied in length and temperature, is used for this purpose, the cross section of which must be dimensioned sufficiently large so that the filaments do not come into contact with the wall. The

The wall temperature or the temperature close to the wall of the so-called post-heater is determined by a further sensor 36 and also regulated.

For further cooling, the filaments pass through the cooling shaft 57, which in the example is ventilated transversely to the thread running direction. The cooling air is sucked off in the connection 37, whereby cooling air is led to the filaments 27 and at the same time vapors which cause the Dispose of filaments 27 and which can be hazardous to health, are removed in a targeted manner.

The suction of the air on one side of the cooling shaft 57 causes an inflow on the other

Page. In order to avoid air turbulence, the air must first pass through a flow grille 38 and an air inlet from another side, for example through the downpipe 39, must be prevented. The same amount of air can be blown in through the flow grille 38 as is discharged opposite.

After passing through the downpipe 39, the filaments 27 are guided into the spinning machine 56. According to the present invention, all the devices downstream of the cooling shaft 57 are referred to as spinning machines 56. In a first step, the filaments 27 come into contact with a preparation device 40, which envelops the filament bundle, which now forms a closed thread 42, with an oily film which ensures further processing before the thread is gripped by the first godet 41 and is continuously drawn off as a solidified thread 42 spun from a melt.

The filaments can also be rotated by a false twist device (not shown) arranged before or after the preparation device 40, which leads to a bundling of the filaments already in the spinning shaft or downpipe.

Depending on the cooling process, the preparation device 40 can be arranged more or less far away from the spinneret 30. For slip-free withdrawal of the thread 42, it is the rule that after about half a loop of the first godet 41 it wraps around a second godet 41 'in the same way, or the thread 42 is passed several times around both godets 41, 41'.

There are several variants for the further running of the thread 42. So this can be fed directly to a winder 43 and wound into the coil 44. It is also possible to stretch the thread 42, for example, between the take-off godets 41, 41 'and another godet duo 45, 45' or between this and a third godet duo 46, 46 '. Heat treatment before winding is also possible. The fully wound bobbin 44 can also be post-treated in a suitable device, for example a chamber oven, to fully develop its thread structure and properties. When winding up the thread, it should be noted that, depending on the spinning and drawing tension which is established, the thread tends to relax by shortening it. If the thread is wound onto the bobbin 23 with too high a tension, the winding tube, bobbin and thread can be deformed, particularly at their crossover points, when producing a cross-wound package. It is therefore important to increase the follow-up of the winder speed compared to the speed of the last godet duo until soft and easily recoverable coil windings are formed. A thread tension of 0.02 to 0.10 cN / dtex can be given as a guideline.

In a further embodiment variant, which is shown in FIG. 3, the filament bundle does not cross. but with a cooling shaft 57 parallel to the direction of flow with air or an inert gas. The structure of the spinning head 25 and the spinning machine 56 corresponds to that of FIG. 2. The cooling shaft 57 is constructed as follows:

Behind the reheating zone 35, the thread runs through a porous tube 50, e.g. made of sintered metal. This tube 50 is used to blow in air or inert gas from the outside via a double jacket. This gas flow has the task of setting a defined axial temperature profile in the thread 42 in the following downpipe 51, which promotes the formation of ordered structures in the polymer and a further increase in the turnover of the chemical chain growth reactions. Both processes improve the thread properties. The downpipe 51 can be heated from the outside (electrically, with steam or a liquid heat transfer medium). Its length depends strongly on the chemical composition of the polymer and on the thread speed. Systems with slow post-reaction and structure formation require long lengths.

At the lower end of the downpipe 51 there is a second porous tube 52 with a double jacket, through which the gas flow is sucked outwards. A further device 53 of this type can be arranged below it, through which a gas flow is introduced which cools the thread 42 and prevents the escape of (health) harmful gases. This gas flow rises and is sucked off in 52.

When the thread 42 exits from 53, the chemical and physical processes in the thread 42 must be completed to such an extent that the treatment that now follows is not impaired or prevented by stickiness.

In a preferred embodiment, a false twist is mechanically applied to the thread 42 at this point, which leads to the welding of the individual filaments in the downpipe. The same effect is achieved if the thread 42 is passed through a swirl nozzle. The further procedure corresponds to that according to FIG. 2.

The invention is described in more detail below by three examples. The method was carried out with a device according to FIG. 1 in conjunction with FIG. 2.

example 1

Chemical formulation g / mole composition polytetrahydrofuran (P-THF) 2,000 1,000 n mol

Hexamethylene diisocyanate (HMDI) 168 1,896 n mol

Ethanolamine-1,2 (EA-1,2) 61 0.896 n mol e-caprolactam content of

(Melting aid) 113 4.0% by mass

According to the recipe listed, the

Prepolymer production as follows:

The P-THF was melted in a heating chamber 1 and dried at a temperature of 50 ° C. and with a vacuum of about 1 mbar and in the presence of a drying agent for about 48 hours. The required amount (determined gravimetrically) was fed to the stirred reactor 16. At the same time it was followed made sure that the other components were in a sufficiently pure and dry form.

This was followed by a brief evacuation of the stirring reactor with subsequent nitrogen exposure. After the contents of the stirred reactor had been heated to 80 ° C., the diisocyanate was added, with vigorous mixing being carried out using an anchor stirrer. The stirred reactor was then brought to a temperature of 120 ° C. and left at this level for 2.5 hours.

The temperature was then reduced to 100 ° C. When this temperature was reached, e-caprolactam was added as the melting aid and

Homogenized for 1 hour at this temperature. After the contents of the stirred reactor had cooled to 80 ° C., the chain extender was added. This was followed by a mixing time of about 0.5 hours. The prepolymer was then metered into the twin-screw extruder.

The twin screw extruder used here had the following features:

Screw diameter: 28 mm

Screw length: 780 mm

Number of heating / cooling zones: 7

Snails: rotating in the same direction,

Thread profiles, continuously decreasing pitch

The prepolymer was metered in such a way that the screws in the feed shaft 20 were filled, normal pressure prevailing in the feed shaft 20. The temperature profile was steadily increasing. The heating zone temperature temperature ranged between 150 and 180 ° C. The extruder ran at a speed of 30 rpm. The pressure at the extruder head was 21 bar with a throughput of 500 g / h. The pressure pump 23 conveyed the melt in a line 24, heated by heat transfer medium of 185 ° C., of approximately 2300 mm in length and a diameter of 7 mm to the spinning pump 28 and the spinning head 25.

The spinning head 25 had a temperature of 217 ° C. His gear spinning pump 28 was set to a delivery rate of 500 g / h. In the spin pack 29, the melt flowed through a sieve fabric with a mesh size of 40 μm and a 5 mm thick sintered metal plate with a grain size of 150 μm before it emerged from five bores of a spinneret 30 as a melt jet. The bores had a diameter of 0.5 mm and a capillary length of 1.0 mm. The five solidifying filaments 27 passed through a post-heating zone 35 of 100 mm in length and 100 ° C. temperature.

Then they entered the cooling shaft 26. In this, an air flow created by suction (37), fed from the ambient air at 20 ° C. and moved transversely to the thread run at 0.3 m / s, cooled the filaments 27 to such an extent that they were reinforced on the preparation nozzle 40 Thread 42 could be bundled and prepared. The total distance between the spinneret 30 and the preparation nozzle 40 was approximately 2 m in this case.

With the godet duo 1 (41, 41 ') the thread 42 was pulled out of the spinning zone at 50 m / min and with slight tension by Duo 2 (45, 45') 55 m / min and Duo 3 (46, 46 ') were fed to the winder 43 at 60 m / min and wound up as a coil 44 at 66 m / min.

The threads had a fineness of Tt = 1284 dtex, a tensile strength of R _H = 0.56 cN / dtex, an elongation at break of e _H = 875%, a breaking tension R _B , calculated according to the formula R _B = R _H (l + e _H / 100%) of R _B = 5.46 cN / dtex and an elastic stretch component after 3 x 300% cyclical strain loading of e _el3 = 87.8%.

Example 2

Five filaments, which had been produced in the same way as in Example 1, were drawn off from Duo 1 at 250 m / min, fed to the winder via Duo 2 at 275 m / min and Duo 3 at 300 m / min, and there at 283 m / min wound as a thread to the coil 44.

The corresponding property values were:

Tt = 304 dtex; R _H = 0.69 cN / dtex; e _H = 469%; R _B = 3.93 cN / dtex, and e _{c! 3} = 78.0%.

This thread was then dried on the bobbin 44 for 24 hours at 30 ° C. under vacuum and heat-treated at 120 ° C. for 1 hour. After this treatment, it had the following property values:

Tt = 269 dtex; R _H = 0.58 cN / dtex; e _H = 756%; R _B = 4.96 cN / dtex; and e _el3 = 87.0%. Example 3

The conditions for the prepolymer production corresponded to those of Examples 1 and 2.

Compared to these examples, however, the delivery rate of the spinning pump was reduced to 300 g / h on the one hand (Examples 3a, 3b), and on the other hand the extruder throughput was increased to 1.0 kg / h (Example 3b).

The difference in the melt flow was discharged through a bypass valve in front of the spinning head.

As the extruder throughput increased from 0.5 to 1.0 kg / h, the heating zone temperatures increased under the same other conditions. The maximum heating zone temperature on the extruder was now 190 ^β C, that of the spinning head was increased from 217 to 221 ° C. All other settings corresponded to example 1.

The following thread properties were determined, where m, Ex extruder throughput and m Sp means spinning pump throughput. The difference between extruder throughput and spinning head throughput was discharged before the spinning head.

^m Ex ^m Sp Tt ^e el. 3 g / hg / T- dtex cN / dtex% cN / dtex%

3a 500 300 722 0.51 744 4.30 86.2

3b 1000 300 718 0.49 759 4.21 83.1

Claims

claims

1. A process for melt spinning polyurethane and / or polyurethane urea, characterized in that a) a prepolymer is prepared containing a reaction product of an organic diisocyanate and a polymeric diol by mixing at 50 to 150 ° C, b) that Temperature level is lowered by about 5 to 50 K and a gel and / or melting aid is added in the liquid state, c) a chain extender is added to this prepolymer while maintaining its molten state with stirring, d) this Prepolymer in the molten state is fed to an extruder, the polymerization being carried out in the extruder at elevated temperature, and e) this polymer melt is spun through spinnerets to form polyurethane and / or polyurethane urea filaments.

2. The method according to claim 1, characterized in that in the preparation of the prepolymer (process step a) first the polymeric diol in the liquid state and then mixed in the organic diisocyanate component in the liquid or molten state with stirring and the reaction to complete or almost complete implementation.

3. The method according to claim 1 or 2, characterized in that a molar ratio of diol to diisocyanate of 1: 1.1 to 1: 10.0 is maintained.

4. The method according to claim 3, characterized in that a molar ratio of 1: 1.4 to 1: 4 is maintained.

5. The method according to at least one of claims 1 to 4, characterized in that the chain extender (method step b) is added while keeping the melt temperature constant.

6. The method according to at least one of claims 1 to 5, characterized in that the chain extender and / or the additives is / are added simultaneously with the gel and / or melting aid or directly into the extruder.

7. The method according to at least one of claims 1 to 6, characterized in that the prepolymer at

Process steps a, b and / or c, additives such as stabilizers, plasticizers, lubricants, spinning aids, flame retardants, pigments, dyes, color auxiliaries or emulsifiers are added.

8. The method according to at least one of claims 1 to 7, characterized in that one works with a double screw extruder, the so dimensioned and operated that a complete or almost complete polymerization of the prepolymer is achieved.

9. The method according to claim 8, characterized in that a co-rotating twin screw extruder is used.

10. The method according to at least one of claims 1 to 9, characterized in that the prepolymer, which is obtained after step c, temporarily stored in the liquid or solid, re-meltable state and fed to the extruder if necessary.

11. The method according to at least one of claims 1 to 10, characterized in that the polymer melt, which is obtained after step d after the Extruder¬ treatment, is converted into the solid granulated state, so that it is storable, and that this solid polymer product is melted again if necessary and then spun.

12. The method according to at least one of claims 1 to 11, characterized in that the filament /

Filaments are passed through a cooling shaft after leaving the spinneret (s).

13. The method according to claim 12, characterized in that the cooling shaft is ventilated transversely to the thread running direction.

14. The method according to claim 12, characterized in that the cooling shaft is ventilated par¬ allel to the thread running direction.

15. The method according to claim 13 or 14, characterized in that the exhaust air is extracted and carried away.

16. The method according to at least one of claims 1 to 15, characterized in that the filament / the fi laments after leaving the spinneret (s) is / are passed through a post-heating zone in front of the cooling shaft.

17. The method according to at least one of claims 1 to 16, characterized in that in front of the cooling shaft instead of a post-heating zone, a coating with hot air / inert gas is carried out.

18. The method according to at least one of claims 1 to 16, characterized in that the melt viscosity before being fed into the spinning head, measured at the temperature of the melt line, is in the range from 150 to 10,000 Pa ^* s.

19. The method according to at least one of claims 1 to 18, characterized in that is worked at a spinning head temperature in the range of 210 to 240 ° C.

20. The method according to at least one of claims 1 to 19, characterized in that the thread or the

Threads are withdrawn from the spinning zone via godets.

21. The method according to at least one of claims l to 20, characterized in that two or more individual filaments are bundled by false twist after they emerge from the spinneret openings.

22. The method according to at least one of claims 1 to 21, characterized in that the thread or the threads are transported by further godets, between which they are stretched and are / are heated thereon.

23. The method according to at least one of claims 1 to 22, characterized in that the thread or the

Threads between the last godet and the winding in the form of a bobbin run through a longer thread storage path and are or are exposed to a temperature effect which causes a tempering effect.

24. The method according to at least one of claims 1 to 23, characterized in that the thread already wound up is subjected to post-heating.

25. The method according to at least one of claims 1 to 24, characterized in that a carboxylic acid amide is used as the gel and / or melting aid.

26. The method according to claim 25, characterized in that e-caprolactam is used as the carboxylic acid amide.

27. The method according to at least one of claims 1 to 26, characterized in that a proportion of the polar gel and / or melting aid from 1 to

25% by mass of the prepolymer is used.

28. The method according to at least one of claims 1 to 27, characterized in that uncapped and / or capped di-isocyanate is used as the organic di-isocyanate.

29. The method according to claim 28, characterized in that 1,6-hexamethylene diisocyanate is used as the organic di-isocyanate.

30. The method according to at least one of claims 1 to 29, characterized in that dihydroxy polyethers and / or dihydroxy polyesters are used as polymeric diols with a molar mass of 1000 to 3000 g / mol and a molar mass ratio of M _w / M _n <2, 0.

31. The method according to claim 30, characterized in that polytetrahydrofuran is used.

32. The method according to at least one of claims 1 to 31, characterized in that as a chain extender a compound selected from the group of aliphatic dihydroxy compounds, aliphatic and / or arylaliphatic hydroxyamine compounds, aliphatic and / or arylaliphati ¬ cal and / or aromatic diamine compounds or mixtures thereof is used.

33. The method according to claim 32, characterized in that ethanolamine and / or

1,4-butylenediamine and / or piperazine is used.

34. Device for carrying out the method according to at least one of claims 1 to 33, characterized in that at least one temperature-controlled reaction vessel (16) for producing the prepolymer via at least one temperature-controlled feed (17) which is equipped with at least one feed pump (18) operated is connected to the feed shaft (20) of an extruder (49) in such a way that the outlet of the extruder (49) leads via a melt line (24) provided with a pump (23) into the spinning head (25), which in turn leads into a cooling shaft (57) opens, and that the cooling shaft (57) is connected to a spinning machine (56).

35. Apparatus according to claim 34, characterized in that the reaction vessel (16) is connected to containers (1, 2, 3, 4) for pretreating the starting components via heatable supply lines (11).

36. Apparatus according to claim 34 or 35, characterized in that the extruder (49) is a twin-screw extruder with screws running in the same direction.

37. Apparatus according to claim 36, characterized in that the screws have an L / D ratio of 20 to 60.

38. Device according to at least one of claims 34 to 37, characterized in that the spinning head (25) contains a spinning package (29).

39. Apparatus according to claim 38, characterized in that the spin pack (29) consists of filter elements, sealing and support elements and a spinning plate (30).

40. Device according to at least one of claims 34 to 39, characterized in that a reheating zone (35) is arranged between the spinning head (25) and the cooling shaft (57).

41. Device according to at least one of claims 34 to 40, characterized in that the cooling shaft (57) is designed such that ventilation of the filament or filaments transversely to the running direction is possible.

42. Device according to at least one of claims 34 to 41, characterized in that the cooling shaft (57) is designed such that ventilation is designed parallel to the running direction of the filament or the Fila¬ elements.

43. Device according to at least one of claims 34 to 42, characterized in that the spinning machine (56) contains a preparation device (40).

44. Device according to at least one of claims 34 to 43, characterized in that the spinning machine (56) contains, in addition to a first godet (41) and a godet (41 '), at least one further godet duo (45, 45').

45. Device according to at least one of claims 34 to 44, characterized in that at least one false twist device (54) is arranged between the spinning head (25) and the first godet (41).

46. Polyurethane and / or polyurethane urea threads, characterized in that they have been obtained according to at least one of Claims 1 to 33.

47. Polyurethane and / or polyurethane urea threads according to claim 44, characterized in that they have a tear strength of at least 0.45 cN / dtex.

48. Polyurethane and / or polyurethane urea threads according to claim 46 or 47, characterized in that they have an elongation at break of at least 300%.

49. polyurethane and / or polyurethane urea threads according to at least one of claims 46 to 48, characterized in that they according to one

3 x 300% cyclic elongation stress have an elastic elongation share of at least 80%.